carbon cycle

noun

Definition of carbon cycle 

1 : the cycle of carbon in the earth's ecosystems in which carbon dioxide is fixed by photosynthetic organisms to form organic nutrients and is ultimately restored to the inorganic state (as by respiration, protoplasmic decay, or combustion)

2 : a cycle of thermonuclear reactions in which four hydrogen atoms synthesize into a helium atom by the catalytic action of carbon with the release of nuclear energy and which is held to be the source of most of the energy radiated by the sun and stars

Examples of carbon cycle in a Sentence

Recent Examples on the Web

Shrinking ice sheets shifted the carbon cycle in a way that raised atmospheric CO2, further warming the planet. Scott K. Johnson, Ars Technica, "Ars answers a federal judge’s questions about climate change," 19 Mar. 2018 These are questions about the carbon cycle—the many interconnected processes by which carbon changes forms and moves throughout the Earth’s atmosphere, oceans, land ecosystems, and even rocks. Scott K. Johnson, Ars Technica, "Ars answers a federal judge’s questions about climate change," 19 Mar. 2018 Some of what’s important is invisible — the water cycle, the carbon cycle. Don Stacom, Courant Community, "From Vernal Pools To A 200-Foot Cliff: Tilcon And New Britain's Watershed," 27 May 2018 Signs of Civilization Finding signs of an altered carbon cycle would be one big clue to previous industrial periods, Schmidt says. Steven Ashley, Scientific American, "Could an Industrial Prehuman Civilization Have Existed on Earth Before Ours?," 23 Apr. 2018 This timing coincides with a jolt to the carbon cycle and abrupt climate warming, indicated by carbon and oxygen isotopes in sediments. Howard Lee, Ars Technica, "When will the Earth try to kill us again?," 9 Nov. 2017 Every year, a huge group of researchers publishes an analysis of the global carbon cycle, projecting the final tally for human emissions for the year based on data through September. Scott K. Johnson, Ars Technica, "2017 to see carbon emissions rise for the first time in years," 13 Nov. 2017 The researchers’ findings also have potential implications for the global carbon cycle. Steph Yin, New York Times, "Who’s Eating Jellyfish? Penguins, That’s Who," 29 Sep. 2017 All extinction episodes, including the dinosaurs’, share one feature or process in common: quick and massive disruptions in the atmosphere’s carbon cycle, usually—but not always—triggered by volcanic activity. Manu Saadia, Ars Technica, "The Ends of the World is a page-turner about mass extinction," 4 Sep. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'carbon cycle.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of carbon cycle

1901, in the meaning defined at sense 1

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The first known use of carbon cycle was in 1901

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More Definitions for carbon cycle

carbon cycle

noun

Medical Definition of carbon cycle 

: the cycle of carbon in living beings in which carbon dioxide is fixed by photosynthesis to form organic nutrients and is ultimately restored to the inorganic state by respiration and protoplasmic decay

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